Shuttle press

ABSTRACT

A press for performing work operations on sheet material having at least one work station at which such work operations are performed. The press includes a pair of secondary pads for retaining the material in position. The secondary pads are movable in a shuttle or reciprocating type motion to progressively and intermittently feed the sheet material through the work station.

United States Patent [191 Vinson 1 Jan. 23, 1973 [54] SHUTTLE PRESS 2,353,405 7/1944 King ....83/277 x 2,549,519 4/1951 Peterson ....83/278X [75] paulv'nmnorangecalf' 3,200,686 8/1965 Norton etal. ..s3/277 73 Assignee; Vinson Industries, Inc" Orange 3,232,156 2/1966 Fuller ..83/39 Calif.

Primary ExaminerAndrew R. Juhasz [22] Filed: June 15, 1970 Assistant Examiner.lames F. Coan [21] Appl' No 46,009 AttrneySmyth, Roston & Pavitt [57] ABSTRACT [52] US. Cl. ..83/206, 83/50, 83/255,

' 83/277,83/282 A press for performing work operations on sheet [51] lnt.Cl. ..B26d /20 material having at least one work station at which 581 Field of Search .83739 40 206 255 Such peratins are pefmmed- The Press [56] References Cited UNITED STATES PATENTS 378,805 2/1888 Richards ..83/277 X cludes a pair of secondary pads-for retaining the material in position. The secondary pads are movable in a shuttle or reciprocating type motion to progressively and intermittently feed the sheet material through the work station.

16 Claims, 19 Drawing Figures 1&5

PATENTEDJAH23 I915 3.712.163

SHEET 8 [1F 6 pdll/ 1 0710 nrramemr SHUTTLE PRESS BACKGROUND OF THE INVENTION Many parts are fabricated from sheet material of various kinds such as aluminum, steel, tape, ceramics, etc. The fabrication of the part typically includes progressively and intermittently feeding the sheet material through several stations of the press with one work operation being performed at each of the stations by appropriate tooling and with the completed part being blanked out at the last station.

It is conventional practice to use automatic feeding mechanisms such as roll or hitch feeds to move the sheet material through the several stations. These feeding mechanisms are not part of the press and are expensive. The typical feed mechanism does not index the sheet material through the stations as accurately as necessary for many precision operations. The feeding mechanism is typically remote from the station at which the work operations are performed and reacts relatively slowly so that the speed of stock feeding consumes a relatively large amount of time.

For example, a roll feed roughly indexes the sheet material and bullet nose pilot punches cooperate with preformed apertures in the sheet material to finally align the sheet material with the tooling. This requires a special work operation to preform the apertures and because of allowable tolerances between the pilot punches and the preformed apertures, the final positioning of the sheet material is not as accurate as is necessary or desirable for many work operations. In addition there is an interval of time when the sheet material is not held in position by the toll feed or the pilot punches.

Many presses are not accurate notwithstanding the manner of stock feed. The recognition of the factors causing such inaccuracy and their solution form a part of the present invention.

In an effort to increase accuracy, it is customary to employ a die set on the press. While this does improve accuracy, equipment cost and set up time are increased.

My copending application Ser. No. 33,592 entitled Shuttle Press filed on May I, 1970, now U.S. Pat. No. 3,673,901, discloses a press having numerous ad.- vantageous features including a shuttle for accurately and rapidly feeding sheet material through the press. In the invention described in the copending application, one of the tools for performing a work operation on the sheet material interlocks with the sheet material. This tool is movable in a shuttle type motion to feed the sheet material through the press.

While the invention of my copending application represents a very substantial improvement over the prior art, it is especially adapted for a press with up to two work stations. In addition, it leaves some possibilities for increasing speed of operation because one of the tool members is involved in the work operation, the stock transfer and the return shuttle movement.

SUMMARY OF THE INVENTION The present invention eliminates the problems described above. One aspect of the present invention is to employ a shuttle which is part of the press itself for feeding the sheet material through the press. The shuttle is closely adjacent the stations of the press at which the work operations are to be performed. The shuttle eliminates the expensive automatic feeding mechanisms used heretofore and provides a much more rapid and accurate feed. Pilot punches and die sets are not necessary with the present invention.

The shuttle concept involves the use of one or more shuttle members which are drivingly engageable with the stock to move the stock a distance corresponding to the distance between adjacent work stations. The shuttle can then be returned to its initial position and caused to impart a second increment of movement to the sheet material in the same manner. Operation of the shuttle is appropriately coordinated with the operation of the tooling and the other parts of the press.

Although the shuttle concept can be implemented in different ways, according to the present invention it is preferred to utilize a portion of the means for retaining the sheet material in position to feed the sheet material through the press. Secondary or shuttle pads are employed to grip or clamp the sheet material and the shuttle pads are movable in a shuttle or reciprocating type motion to intermittently and progressively feed the sheet material through the press.

The shuttle pads are preferably operated by means other than the platen. Accordingly, the platen need not travel with the sheet material and can reciprocate vertically in a predetermined timed relationship to the rate of indexing of the sheet material. Thus, the press can have any number of work stations without in any way slowing down the operation of the press.

During the performance of a work operation on the sheet material, the shuttle pads clamp the sheet material in position. Following the work operation or near the completion thereof, the shuttle pads unclamp the sheet material and move to a new position at which the shuttle pads again clamp the sheet material. The shuttle pads then move to index the sheet material.

During the time the shuttle pads are not clamping the sheet material, the sheet material is retained in position by suitable means such as a primary pressure pad which is operatively associated with the platen. Accordingly, the primary pad and the shuttle pads cooperate to tightly retain the sheet material in position throughout the full operational cycle of the press and accordingly the accuracy of the press is very good.

To reduce frictional losses, the shuttle pads do not slidably engage other portions of the press during the reciprocating movement thereof.

Although the movement of the shuttle pads can be implemented in different ways, it is preferred to use a carriage beneath the shuttle pads. The carriage is mounted for movement along a first path which may be in a plane parallel to the plane of the sheet material. The carriage and the shuttle pads are drivingly connected for movement of the shuttle pads with the carriage along such first path. At least one of the shuttle pads is mounted for movement relative to the carriage along the second path, and this permits the pads to clamp and unclamp the sheet material. Movement of the carriage along the first path provides the stock feeding and pad return movement. These movements can be coordinated by suitable cams.

Numerous other factors contribute to the speed and accuracy of the press of this invention. For example, substantially all of the press is located at elevation beneath the platen thereby lowering the center of gravity of the press and tending to stabilize it. The platen and the shuttle pads are mounted on suitable posts which extend downwardly from the platen with each of the posts being supported by relatively long bearings. To further improve the speed of the press, the platen and shuttle pads are preferably driven by full harmonic cams which are much faster than an eccentric. The cams can be changed to thereby permit full programming of the operations performed by the press.

According to the present invention, it is preferred to move the carriage along a line generally parallel to the plane of the sheet material utilizing a cam and an arm mounted for pivotal movement about a pivotal axis. The length of stroke of the carriage can be varied by moving of the pivot axis of the arm while holding the arm in position.

Although the adjustable pivot may take many different forms, it is preferred to utilize a supporting member and to provide slots in both the arm and the supporting member. A supporting shaft extends through both of the slots and bearing means is mounted on the supporting shaft for mounting the arm on the shaft for pivotal movement relative to the supporting shaft about a pivotal axis. Means are provided for releasably drivingly connecting at least a portion of the bearing means to the arm for pivotal movement therewith. The arm is releasably retained on the bearing means so that the bearing means and the supporting shaft can be moved in the slots relative to the arm and the supporting member to thereby move the pivot axis relative to both of the arm and the supporting member.

The press of this invention can be utilized to perform plural work operations in a single hit or stroke of the platen. To accomplish this the die preferably includes an outer die having an opening therein and an inner die for cooperation with a portion of the punch for performing a first work operation. The inner die is mounted for movement in the opening of the outer die.

As the toolholder and punch are moved downwardly toward the sheet material, the punch engages the sheet material and cooperates with the inner die to perform a first work operation. At about the time the first work operation is completed or subsequently thereto, a drive member, other than the punch, urges the inner die downwardly to thereby allow a second portion of the punch to cooperate with the opening in the outer die to perform a second work operation on the sheet material. The inner die is forced out of the way by the drive member so that the sheet material is not substantially squeezed between the outer die and the punch during the second work operation. If the punch itself were to move the inner die away, the sheet material may be coined somewhat between the punch and the inner die. The present invention eliminates this undesirable coining effect.

The present invention also provides for adjustment of the position of the primary pad relative to the platen. This is accomplished by utilizing adjustable connection means between the primary pad and the platen.

The invention, both as to its organization and method of operation together with further features and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing tooling and shuttle pads constructed in accordance with the teachings of this invention with the tooling being in a position to cooperate to perform a work operation on the sheet material.

FIG. 2 is a sectional view similar to FIG. 1 with the tooling advanced to perform a work operation on the sheet material.

FIG. 3 is a sectional view similar to FIG. 2 with the upper shuttle pad raised slightly above the upper surface of the sheet material.

FIG. 4 is a sectional view similar to FIG. 3 after the shuttle pads have been moved to a new position along the sheet material and have again clamped the sheet material in preparation for indexing of the sheet material.

FIG. 5 is a side elevational view partially in section of a preferred form of press for carrying out work operations such as those shown in FIGS. 1-4.

FIG. 6 is a sectional view taken generally along line 66 in FIG. 5 with some parts of the press being shown in front elevation.

FIG. 6a is a side elevational view of another form of shuttle pad arm which is usable with the press of FIGS. 5 and 6.

FIG. 6b is a sectional view taken generally along line 6b6b of FIG. 6a.

FIG. 7 is an elevational view partially in section taken generally along line 7-7 of FIG. 5 and illustrating the arm which controls horizontal movement of the shuttle pads.

FIG. 8 is a sectional view taken generally'along line 88 of FIG. 5 and showing a preferred mechanism for adjusting the location of the pivot axis of the arm which controls horizontal shuttle pad movement.

FIG. 8a is a view taken generally along line 8a8a in FIG. 8.

FIG. 8b is a sectional view taken generally along line 8b8b in FIG. 8.

FIG. 9 is a side elevational view partially in section of a platen, toolholder and tools which may be utilized in the press of FIG. 5.

FIG. 10 is a fragmentary section view illustrating a modification of the invention in which a washer-like element is formed in a one-hit operation. In FIG. 10, the punch is advanced sufficiently to have performed the first work operation on the sheet material.

FIG. 11 is'a sectional view similar to FIG. 10 with the punch having been advanced to perform the second work operation.

FIG. 12 is a fragmentary sectional view showing how the inner die can be used to return the blanked out part to the remainder of the sheet material.

FIG. 13 is a sectional view through a preferred form of tooling for carrying out the work operations shown in FIGS. 10-12.

FIG. 14 is a side elevational view partially in section of the preferred form of tooling shown in FIG. 13.

FIG. 15 is a side elevational view showing a second form of primary pad adjustable means.

DESCRIPTION OFTHE PREFERRED EMBODIMENTS The concept relating to retaining and indexing of the sheet material through a work station can best be understood by reference to FIGS. .1-4. In FIG. 1, a die plate 11 is suitably fixedly mounted on a support member 13 having an upper surface 15. Although the construction of the die plate 11 will vary depending upon the number and type of work operations which are to be performed, in the embodiment illustrated the die plate 11 includes die cavities l7 and 19 located at first and second work stations, respectively. The size and cross sectional configuration of the die cavities 17 and 19 will depend upon the nature of the work operation which is to be carried out at the respective station; however, in the embodiment illustrated, the upper end portions of the cavities 17 and 19 are cylindrical with the portions therebelow flaring outwardly to facilitate slug or part removal.

The die plate 11 has an upper surface 21 against which sheet material 23 may rest. The sheet material 23 may be of any kind upon which it is desired to perform a work operation. For example, the sheet material 23 may be aluminum, steel, ceramic, precious metal, cloth, tape, etc.

A punchholder 25 which may be of any suitable construction, carries first and second punches 27 and 29 and a primary pressure pad 31. The punchholder 25 is suitably mounted for vertical movement toward and away from the die plate 11 and the punchholder is retained against horizontal movement. The primary pressure pad 31 is drivingly connected to the punchholder 25 for vertical movement therewith by a resilient driving connection which also permits relative vertical movement therebetween. Such driving connection between the punchholder 25 and the primary pressure pad 31 may be of the type described more fully hereinbelow with reference to FIG. 9.

The size and configuration of the punches 27 and 29 depend upon thetype of work operations which it is desired to perform on the sheet material 23. In the embodiment illustrated, the punch 27 is a cylindrical piercing punch and the punch 29 has a cylindrical tip or end portion 33 and a cylindrical body ,35 with .the punch 29 being adapted to blank out a part. The punches 27 and 29 extend through cylindrical openings 37 and 39, respectively, in the primary pressure pad 31. Although the tooling is illustrated as including particular punches and die cavities, it should be understood that the invention is not limited to the use of any particular kind of tooling. Furthermore, the number of work stations illustrated in' FIG. 1 as well as the number of punches and diecavities are merely illustrative.

The sheet material 23 is progressively and intermittently advanced through the'work stations by an upper shuttle pad 41 and a lower shuttle pad 43. The shuttle pads 41 and 43 are mounted for movement horizontally in the plane of the sheet material 23 and the upper shuttle pad 41 is also mounted for vertical movement. A preferred form of mounting of the shuttle pads 41 and 43 is described more fully hereinbelow with reference to FIGS. 5-8.

In the embodiment illustrated, the shuttle pads 41 and 43 have openings 45 and 47, respectively, and the die plate 11 and the primary pad 31 are located within such'openings. Thus, the pads 41 and 43 circumscribe the die plate 11 with portions of each of the pads being on opposite sides of the die plate. Although the pads 41 and 43 could be of different construction, preferably each of the pads is an integral unit in the sense that all portions thereof'are rigidly affixed to each other to thereby assure accurate and uniform movement of the entire pad.

In the position shown in FIG. 1, the shuttle pads 41 and 43 clampingly engage opposite faces of the sheet material 23. Accordingly, with the pads 41 and 43 themselves firmly held in a fixed position, the sheet material 23 is also retained in such fixed position. The shuttle pad 43 has a lower face 49 which is spaced upwardly from the surface 15 of the support member 13 to thereby prevent frictional losses during horizontal movement of the lower shuttle pad.

In many instances, it will be preferred to perform the work operations with the components being in the spatial orientation shown in FIGS. 14. However, it should be understood that the invention is not limited to performance of the work operations in this orientation. Accordingly, words such as upper, lower, horizontal and vertical are used herein merely to aptly describe the specific embodiment and not to limit the invention.

FIG. 2 illustrates the same components shown in FIG. 1 with the punchholder 25 having been advanced to cause the punches 27 and 29 and the die cavities 17 and 19 to cooperate to perform work operations on the sheet material. By way of example, the punch 27 and the die cavity 17 cooperate to remove a slug 51 of the sheet material to thereby form an aperture 52 in the sheet material. The punch 29 and the die cavity 19 cooperate to blank out a washer-like element 53.

During the initial advancing phases of the punchholder 25 toward the die plate 11, the primary pressure pad 31 travels with the punchholder and ultimately engages the sheet material 23. Further downward movement of the punchholder 25 compresses the resilient connecting means (described hereinbelow with reference to FIG. 9) to thereby cause the primary pressure pad 31 to resiliently squeeze the sheet material therebelow against the upper surface 21 of the die plate 11. In this manner, the primary pressure pad 31 cooperates with the die plate 11 to assist in retaining the sheet material in position during the performance of the work operations. Upon further advance of the punchholder 25, the tooling cooperates as described hereinabove to form the aperture 52 and to blank out the washer-like element 53. If desired the tooling may perform an impact piercing operation as described in my said copending application.

As shown in FIG. 2, the shuttle pads 41 and 43 continue to tightly clamp the sheet material 23 in position. The clamping action of the shuttle pads 41 and 43 should continue at least until the primary pressure pad and the die plate 1 l clamp the sheet material with sufficient force to prevent movement thereof and/or until the punches 27 and 29 interlocked with the sheet material by virtue of the apertures punched thereby. Preferably, the pads 41 and 43 remain in clamping engagement with the sheet material 23 during the performance of the work operations.

Once the primary pad 31 and the die plate 11 grip the sheet material 23 with sufficient force, the upper shuttle pad 41 is moved upwardly to thereby remove the pads 41 and 43 from clamping engagement with the sheet material as shown in FIG. 3. Preferably upward movement of the upper shuttle pad 41 begins at or just prior to the completion of the work operations.

Next, with the shuttle pads 41 and 43 in the relative vertical orientation shown in FIG. 3, the shuttle pads are moved horizontally to the right as viewed in FIGS. 1-4. The shuttle pads 41 and 43 move an accurately predetermined distance, and then the upper shuttle pad 41 is moved downwardly to again clamp the sheet material between the pads 41 and 43 as shown in FIG. 4. Such horizontal movement of the pad 43 is carried out with the lower face 49 thereof being in spaced relationship to the surface 15 of the support member 13.

It is important that the sheet material 23 be maintained in position during the movement of the shuttle pads 41 and 43 from the position shown in FIG. 3 to the position shown in FIG. 4. According to the embodiment illustrated, this is accomplished by the primary pressure pad 31 squeezing the sheet material against the upper surface 21 of the die plate 11 with spring pressure and also by the punches 27 and 29 which remain within the apertures formed thereby in the sheet material 23.

When the shuttle pads 41 and 43 grip the sheet material 23 sufficiently to adequately retain same in position, the punchholder 25 begins its upward movement. Preferably this does not occur until the upper shuttle pad 41 has completed its downward clamping movement. When the punches 27 and 29 have cleared the apertures in the sheet material 23 formed thereby, the shuttle pads 41 and 43 move as a unit an accurately predetermined distance to the left to the position shown in FIG. 1 to thereby index the sheet material. In the embodiment illustrated, such indexing involves moving of the aperture 52 (FIG. 2) formed in the preceding work operation by the punch 27 and the die cavity 17 into precise alignment with the axis of the end portion 33 of the punch 29. In addition, a new section of the sheet material is brought into registry with the punch 27 and the die cavity 17. The process can then be repeated as described above. If desired the end portion 33 could include an axial projection of bullet nose configuration for cooperating with the aperture 52 to finally align the punch 29 and the aperture. If this were done, the pads 41 and 43 would be operated to instantaneously release the sheet material to permit such alignment.

FIGS. -9 illustrate a press 61 which is particularly adapted for carrying out the sequence of operations shown in FIGS. 1-4. However, the press 61 contains various features and advantages and is not limited to performing the operations described with reference to FIGS. 14.

Portions of the press 61 shown in FIGS. 5-9 corresponding to components shown in FIGS. 1-4 are designed by corresponding reference numerals followed by the letter a. The press 61 includes a base 63, four vertical support members 65, 67 (FIG. 5), 69 and 71 (FIG. 6) and a horizontal support member 13a.

With reference to FIG. 6, a portion of the vertical support member 71 is cut away to provide space for a bearing block 73. The bearing block 73 supports roller bearings 75 and 77 in coaxial relationship. The bearings 75 and 77 have inner rings 79 and 81, respectively, and a tubular drive shaft 83 is suitably connected to the inner rings 79 and 81 for rotation therewith. A shaft 85 having an enlarged end portion 87 is received within the tubular drive shaft 83 and is affixed thereto by a key 89 (FIG. 5). The key 89 causes the shaft 85 to rotate with the drive shaft 83, but permits relative axial movement therebetween, and thus the key 89 acts like a spline. A handwheel 91, which also serves as a flywheel, is affixed to the shaft 85 by a screw 93 and a shoulder 95 on the shaft 85.

With reference to FIG. 6, an electric motor 97 drives the drive shaft 83 through a gear box 99, a stub shaft 101, and a splined coupling 103. The splined coupling 103 includes a driving member 105 and a driven member 107 with the latter being suitably rigidly connected to the end of the drive shaft 85. The driving member 105 is suitably mounted on the stub shaft 101 for rotation therewith and so as to permit relative axial movement therebetween and such connection may be formed by splines (not shown) if desired. The members 105 and 107 have cooperating teeth or splines 109 on the cooperating confronting end faces thereof to thereby drivingly connect the members 105 and 107. A spring 111 acts between the driving member 105 and the gear box 99 to urge the teeth 109 of the members 105 and 107 into driving relationship. The enlarged end portion 87 of the shaft 85 is mounted within the coupling 103 with the end face thereof being engageable with the driving member 105.

From the foregoing it will be apparent that the motor 97 drives the drive shaft 83 through the gear box 99, the stub shaft 101, the driving member 105 and the driven member 107. Similarly, the shaft 85 rotates with the drive shaft 83 because the key 89 drivingly interconnects these two shafts. The handwheel 91 rotates with the shaft 85 and serves as a flywheel.

In addition, with the motor 97 turned off, the handwheel 91 may be used to facilitate start up of the press. To accomplish this, the handwheel 91 is urged axially inwardly to thereby force the end portion 87 of the shaft 85 against the driving member 105 to thereby urge the latter axially away from the driven member 107 against the biasing force of the spring 111. The key 89 permits this relative axial movement between the shaft 85 and the drive shaft 83 to occur.

This separates the splines or teeth 109 and breaks the driving connection between the motor 97 and the drive shaft 83. This allows rotation of the drive shaft 83 by the handwheel 91.

A pair of cams 113 and 115 are mounted on the drive shaft 83 for rotation therewith by a pair of keys 117 and 119, respectively. The cams 113 and 115 are retained on the drive shaft 83 by a nut 121 which is received on the end portion of the drive shaft. The cams 113 and 115 are held in axially spaced relationship by a spacer 123 which is mounted on the drive shaft 83. The cam 113 has an internal platen cam track or cam surface 125 and an external shuttle pad cam surface 127. The cam 115 has an internal stock transport cam surface 129.

As shown in FIGS. 5 and 6, the press 61 includes a platen 131 which carries a punchholder 25a (FIG. 5)

and which is moved vertically by the cam surface 125 in response to rotation ofthe cam 113. The platen 131 is supportedby a pair of platen posts 133 and 135 (FIG. 6), the lower ends of which are rigidly interconnected to a bracket 137. The posts 133 and 135 are slidably supported for vertical movement by upper bearings 139 and lower bearings 141. The bearings 139 and 141 are retained in bearing blocks 143 which are rigidly mounted on the support members 69 and 71, respectively.

A cam follower 145 drivingly joins the bracket 137 and the platen cam surface 125. The upper end of the cam follower 145 includes a stud 147 which is slidably received in a bore 149 of the bracket 137. The opposite ends of the stud 147 are threaded and nuts 151 cooperate with the threaded portions of the stud 147 to rigidly mount the cam follower 145 on the bracket 137 with the relative axial position of the cam follower 145 and the bracket 137 being adjustable by the nuts 151.

The cam follower 145 also includes a roller 153 or other suitable cam following element which is received in the platen cam surface 125. Accordingly, rotation of the cam 113 causes cooperation between the cam surface 125 and the roller 153 to move the platen 131 and the punchholder 25a (FIG. vertically, such motion being transmitted through the cam follower 145, the bracket 137, and the platen posts 133 and 135. Obviously, the cam surface 125 can be designed so that the desired vertical motion of the platen 131 and hence of the punchholder 25a can be obtained.

As shown in FIG. 5, the press 61 also includes an upper shuttle pad 41a and a lower shuttle pad 43a. The cam surfaces 127 and 129 control the movements of the pads 41a and 430, such movements being of the type described hereinabove with reference to FIGS. 1-4.

The upper pad 41a may be generally rectangular in plan and has an opening 45a therein with the primary pressure pad 31a lying within such opening. A plurality of vertical posts 155 (two being illustrated in FIG. 5) are suitably rigidly mounted to the upper shuttle pad 41a and project downwardly through slots 157 and sleeve bearings 159, the latter being mounted in and carried by a carriage 161. The upper shuttle pad 41a is urged downwardly by springs 163 which bear against a plate 165 which in turn is rigidly affixed to the lower end of the posts 155. Thus, the upper and lower ends of the post 155 are rigidly secured together by the upper shuttle pad 41a and the plate 165, respectively. As shown in FIG. 5, the springs act between the carriage 161 and the upper surface of the plate 165 to resiliently urge the upper shuttle pad 41a downwardly.

A shuttle pad arm 167 (FIG. 5) is pivotally mounted by a pin 169 to a plate 171 with the latter being suitably rigidly affixed to the support member 65. The shuttle pad arm 167 in the embodiment illustrated is in the form of a bell crank and the upper end thereof carries a shoe 173 which is pivotally affixed to the arm 167 asby a screw 175. The upper surface of the shoe 173 bears against and is slidable along the lower surface of the plate 165 as shown in FIGS. 5 and 6. A follower member in the form of a roller 177 is rotatably mounted on the lower end of the shuttle pad arm 167. The roller 177 rolls along the shuttle pad cam surface 127 of the cam 113. Thus, the cam surface 127 and the roller 177 cooperate to move the upper shuttle pad 41a vertically. Specifically, upward movement of the roller 177 pivots the arm 167 about the pin 169 to force the shoe 173 upwardly against the biasing action of the springs 163. Such upward movement of the shoe 173 moves the posts and hence the upper shuttle pad 41a upwardly. The sliding contact between the shoe 173 and the plate accommodates the pivotal movement of the shuttle pad arm 167 and the springs 163 are operative to move the upper shuttle pad 41a downwardly as permitted by the cam surface 127.

The shuttle pads 41a and 43a are moved horizontally by the carriage 16]. Specifically, the carriage 161 is mounted for generally horizontal movement by rods 179 and 181 which project through the carriage 161 and which are suitably affixed thereto. The opposite ends of the rods 179 and 181 are supported for horizontal sliding movement by bearings 183 and 185 mounted on the vertical support members 65 and 67, respectively. Bearings 187 support the rods 179 and 181 intermediate the ends thereof and are located in a block member 189 which may be rigidly mounted on the side members 69 and 71. As the posts 155 project through the carriage 161, horizontal movements of the carriage will result in horizontal movement of the posts 155 and the upper shuttle pad 41a.

The lower shuttle pad 43a is suitably rigidly affixed as by connectors 191 (FIG. 5) to the carriage 161. The connectors 191 project through the slots 157. Accordingly, horizontal movement of the carriage 161 also results in corresponding horizontal movement of the shuttle pad 430. The sliding connection between the shoe 173 and the plate 165 does not interfere with the horizontal movement of the carriage 161 and the shuttle pads 41a and 43a.

Horizontal movement is transmitted from the stock transport cam surface 129 to the carriage 161 by a stock transport arm 195 (FIGS. 5 and 7). The stock transport arm 195 is connected by an adjustable pivot 197 to the plate 171 for pivotal movement about an axis intermediate the ends of the stock transport arm 195. The upper end of the stock transport arm 195 has a slot 199 therein for receiving a bushing 201 which is generally rectangular in cross section. A pin 203 passes through the bushing and the end portions thereof are received within aligned openings in U-shaped members 205 and 207 (FIG. 7) which receive the rods 179 and 181, respectively. The U-shaped members 205 and 207 are rigidly affixed to the rods 179 and 181, respectively, in any suitable manner such as by set screw 209. Accordingly, movements of the upper end of the stock transport arm 195 are transmitted through the connector members 205 and 207 to the rods 179 and 181.

The lower end of the stock transport arm 195 carries a cam follower element in the form of a roller 211. The roller 211 is received within and cooperates with the cam surface 129 of the cam 115.

Rotation of the cam 115 by the motor 97 causes the cam surface 129 to control the position of the roller 211. This imparts pivotal movement to the stock transport arm 195 about the adjustable pivot 197. Such pivotal movement causes the upper end of the stock transport arm 195 to move the bushing horizontally. Horizontal movement of the bushing 210 imparts a corresponding movement to the carriage 161 through the pin 203, the U-shaped members 205 and 207 and the rods 179 and 181.

The adjustable pivot 197 can be operated to move the pivot point for the stock transport arm 195 without moving the arm itself. It will be appreciated that by moving the pivot axis for the stock transport arm 195 that the amount of horizontal movement imparted to the carriage 161 can be varied for any given cam surface 129. Stated differently, by appropriately adjusting the adjustable pivot 197, the press 61 can be adjusted to provide different distances of horizontal travel for the shuttle pads 41a and 43a. This means that the amount of stock fed in between each work operation can be adjusted and that the distance between stations can be adjusted.

Although the adjustable pivot 197 can be of different constructions, in the embodiment illustrated, the stock transport arm 195 and the plate 171 have elongated slots 213 and 215 (FIGS. 5, 8 and 80), respectively, with the slot 213 in the arm 195 being somewhat wider and longer than the slot 215. The longitudinal sides of each of the slots 213 and 215 are linear and parallel and the two slots are in registry. The plate 171 has channels 217 and 219 on opposite sides thereof with the channels having straight parallel longitudinal sides and extending in the same direction as the slots 213 and 215.

A supporting shaft 221 having a square head 223 and a threaded shank 225 projects through the slots 213 and 215. The square head 223 is slidably received in the channel 219 so that the head can slide along the channel but cannot turn relative thereto. A tubular retainer 227 is slidably received on the shank 225 and has a flange 229 of square or rectangular configuration which is slidably received in the channel 217. The flange 229 cooperates with the channel 217 to prevent relative rotation between the retainer 227 and the plate 171. The square head 223 and the flange 229 are wider than the slot 215 so that they engage opposed portions of the plate 171.

A nut 231 is screwed onto the threaded shank 225 and engages the retainer 227 to force the flange 229 thereof against the plate 217 and to draw the head 223 in the opposite direction against the opposite face of the plate. Accordingly, tightening of the nut 231 results in gripping or clamping of the plate 171 between the head 223 and the flange 229 with such clamping force being sufficient to rigidly mount the Supporting shaft 221 in a preselected position along the plate 171. The retainer 227 also supports the shank portion of the supporting shaft 221.

A cylindrical bushing 233 is supported on the retainer 227 and an outer retainer 235 is mounted on the bushing 233. The retainer 235 has a square section 237 (FIGS. 8 and 8b) which is received in the slot 213 and a flange 239. The square section 237 is sized so as to be slidable in the slot 213 but to be nonrotatable relative thereto as shown in FIG. 8b. The square section 237 is slidable in the slot 213 and cooperates therewith to cause the arm 195 and the retainer 235 to pivot as a unit. Of course the section 237 need not be square, it only being necessary that it have a cross sectional shape which is cooperable with the slot 213 to lock the arm 195 and the retainer 235 for rotation while permitting relative sliding movement of the section 237 longitudinally in the slot 213.

The outer end of the retainer 235 is circular and threaded and a nut 24] is screwed onto the outer end of the retainer 235. The flange 239 and the nut 24] are wider than the slot 213 so that the arm can be clamped between the flange 239 and the nut 241. Accordingly, by tightening of the nut 241, the retainer 235 is placed in tension to thereby cause the arm 195 to be clamped between the surface 243 of the nut 24] and the flange 249 with sufficient force to prevent slidingly movement of the retainer 235 in the slot 213 of the arm 195.

When the arm 195 is pivoted, the nut 241 and the retainer 235 pivot therewith due to the driving connection afforded by the square section 237 and the slot 213. Relative pivotal movement may occur between the retainer 235 and the bushing 233 and/or the busing 233 and the retainer 227. The retainer 227 cannot rotate because the flange 229 thereof is slidably and nonrotatably received in the channel 217. The supporting shaft 221 cannot rotate because the head 223 thereof is slidably and nonrotatably received in the channel 219. With this construction, the pivot axis of the adjustable pivot 197 is the axis of the shank 225 and the bushing 233 and the retainer 235 cooperate to define bearing means for the arm 195.

To adjust the location of the pivot axis, it is only necessary to loosen the nuts 231 and 241. The entire adjustable pivot 197 can then be slid in the slots 213 and 215 to the new position desired whereupon the nuts 231 and 241 are tightened to permit pivotal movement of the arm 195 as described hereinabove. Specifcally, the retainer 235 slides in the slot 213 and the shank 225 slides in both of the slots 213 and 215. The head 223 and the flange 229 slide in the channels 219 and 217, respectively. The arm 195 cannot move during movement of the adjustable pivot 197. The only movement of the arm 195 permitted by the slot 213 and the adjustable pivot 197 is in the direction of the slot 213 and/or about the pivotal axis defined by the adjustable pivot. The upper end of the arm 195 can only move vertically as the carried 161 is preferably suitably locked in position prior to adjusting the pivot 197 and the lower end of the arm 195 can only move along the path defined by the cam surface 129 and such path is not vertical. Alternatively a spring (not shown) could act upwardly on the arm 195 to positively prevent the arm 195 from falling during adjustment of the pivot 197.

If desired, the arm 195 may have indicia 245 (FIG. 5) thereon serving as calibrations which, for a given cam surface 129, indicate the amount of horizontal movement of the shuttle pads 41a and 43a obtainable for a given position of the adjustable pivot 197. if the indicia 245 are used, the adjustable pivot should also include a pointer 247 (FIGS. 5 and 8) movable therewith and having a marking thereon closely adjacent the indicia 245 to permit the operator to readily ascertain the amount of horizontal movement which will be obtained.

FlG. 9 shows the platen 131 having a bore 249 therein for receiving a compression spring 251 and a head 253 of a bolt 255. The stripper bolt 255 projects through the punchholder 25a and is affixed at its lower end to a primary pressure pad 31a. When the platen 131 is moved downwardly, the pressure pad 31a contacts the upper surface of the sheet material 23a and continued downward movement of the platen 131 results in compression of the spring 251 and the consequent application of spring pressure to the sheet material thereby clamping the latter firmly against the die plate 11a. Similarly, during the initial portion of the upward stroke of the platen 131, the pressure pad 31a remains in contact with the sheet material 23a while the spring 251 expands. Ultimately the head 253 strikes the upper surface of the punchholder 25a whereby further upward movement of the platen 131 elevates the pressure pad 31a from the sheet material 23a.

In operation of the press 61, the cams 113 and 115 are rotated by the motor 97 during normal operation of the press and by the hand wheel 91 during setup, it being possible to disengage the motor 97 by moving the handwheel 91 axially to the right as viewed in FIG. 6. When the motor 97 drives the cams 113 and 115, the handwheel 91 rotates with the drive shaft 83 to serve as a flywheel.

Assuming that the platen 131 is initially raised to its uppermost position and that the shuttle pads 41a and 43a tightly grip the sheet material 23a, rotation of the cams 113 and 115 drives the platen 131 downwardly through the cam follower 145, the bracket 137 and the platen posts 133 and-135. During this time, the cam surfaces 127 and 129 dwell so that the shuttle pads 41a and 43a continue to tightly grip the sheet material.

At or near the completion of the downward stroke of the platen 131, the primary pressure pad 31a (FIG. 9) clamps the sheet material 23a against the die plate 11a described in connection with FIG. 9 hereinabovep-With the sheet material 23a-securely clamped, the cam surface 127 pivots the shuttle pad arm 167 upwardly to impart upward movement to the upper shuttle pad 41a through the shoe 173, the plate 165 and the posts 155. This results in the unclamping of the sheet material 23a by the shuttle pads 4la and 43a.

Next, with the sheet material 2311 being tightly clamped in position between the pressure pad 31a and the die plate 11a (FIG. 9), the camsurface 129 imparts pivotal movement to the stock transport arm. 195 to thereby pivot the latter about the pivot axis established by the adjustable pivot 197. This imparts horizontal movement to the carriage 161 through the bushing 201, the pin 203, the U-shaped members 205 and 207 and the rods 179 and 181. Horizontal movement of the carriage 161 moves the lower shuttle pad 43a by virtue of the connectors 19] which connect the carriage and the lower shuttle pad for movement. Because the posts 155 which are joined to the upper shuttle pad 41a project vertically through the carriage 161, horizontal movement of the carriage also imparts horizontal movement to the upper shuttle pad 41a. The sliding contact between the shoe 173 and the plate 165 permits the carriage to move horizontally relative to the shuttle pad arm 167.

The cams 113 and 115 continue to operate the platen 131 and the shuttle pads 41a and 43a in the manner described hereinabove with reference to FIGS. 1-4, it being understood that the cam surfaces could be selected to provide a different mode of operation, if desired. 7

FIGS. 6a and 6b show a modified construction of the shuttle pad arm which permits adjustment of the latter so that the press can readily accommodate different thicknesses of sheet material. Parts of FIGS. 6a and 6b corresponding to parts of FIGS. 5 and 6 are designated by corresponding primed reference numerals, and except as specifically shown or described, the construction of FIGS. 6a and 6b is identical to that shown in FIGS. 5 and 6.

The shuttle pad arm 167' includes a body 401 carrying the roller 177' and pivotally mounted on the plate 171 by a suitable pin or shaft 169'. The body 401 includes spaced web sections 403 and 405 defining a slot 407 therebetween. The arm 167 also includes a member 409 which is pivotally mounted on the pin 169' by a bushing 411 for movement in the slot 407. The member'409 has an arcuatev slot 413 therein and a screw 415 or other suitable element projects through the slot 413 to releasably clamp the web sections 403 and 405 against the member 409. The sloe 173' is pivotally carried by the outer end of the member 409 so that by adjusting the position of the member 409 using the screw 415, the position of the shoe 173' is correspondingly adjusted. This in turn changes the vertical position of the shuttle pad 41a relative to the pad 430.

FIGS. 10-12 illustrate somewhat diagrammatically the performance of two work operations on sheet material in a one-hit operation. FIG. 10 illustrates a punch 271 and a die 273 for performing work operations on sheet material 275. The punch 271 includes coaxial cylindrical sections 277 and 279 with the section 277 projecting axially beyond the section 279. The punch 271 projects through a primary pad 337 which performs the usual sheet material clamping function. As with the other embodiments of the invention, this embodiment of the invention is not limited to use with the particular form of punch illustrated.

The die 273 includes a die plate 281, and outer die 283, and an inner die 285. The outer die 283 has an opening or die cavity 287 therein having a configuration conforming to the configuration of the periphery of the section 279 of the punch 271. Accordingly, in the embodiment illustrated, the opening 287 is generally cylindrical. The outer die 283 is suitably retained in the die plate 281 and the die plate is in turn suitably fixedly mounted on the press.

The inner die 285 has a cavity 289 sized to cooperate with the section 277 to permit the piercing of an aperture 291 in the sheet material 279. The upper end of the inner die 285 is slidably received within the opening 287.

The inner die 285 is suitably mounted on a bolster or plate-like member 293 which is urged downwardly by a plurality of springs 295 which bear against a lower bolster 297. The lower bolster 297 is fixedly mounted relative to the die plate 281, and the bolster 293 and the inner die 285 are mounted for generally vertical movement relative to the bolster 297 and the die plate 281. The springs 295 are of sufficient force to maintain the inner die 285 in the position shown in FIG. 10 during the piercing of the sheet material 285 to form the aperture 291. In this position, the upper face of the inner die 285 is substantially coplanar with the upper face of the outer die 283. The upward travel of the bolster 293 can be limited to any suitable manner.

The formation of the aperture 291 creates a slug 299 which escapes through the die cavity 289, an opening 301 in the bolster 293 and a tubular slug guide 303.

In FIG. 11, the section 279 cooperates with the die cavity 287 to blank out a washer-like element 305 and to form an aperture 306 in the sheet material 275. To prevent coining of the sheet material which ultimately forms the washer-like element 305 between the section 279 and the inner die 285, the inner die is retracted prior to the application of sufficient squeezing force to the sheet material to achieve any adverse effect.'According to the present invention, this is accomplished by a drive member 307 which is engageable to the bolster293 to move the latter downwardly. Preferably, the drive member 307 is driven by a suitable driving connection 309 from the same means 310 which drives the punch 271. Accordingly, the drive member 307 may be driven by the toolholder for the punch 271 or by the platen. In any event, the drive member 307 descends with the punch 271 and drivingly engages the bolster 273 at some time after the piercing operation shown in FIG. 10 and before the sheet material 275 is substantially squeezed between the section 279 and the inner die 285.

As shown in FIG. 11, the drive member 307 descends with the punch 271 to force the bolster 293 and the inner die 285 downwardly against the biasing force of the springs 295. In this manner, the inner die 285 is mechanically retracted by means other than the punch 271 to thereby prevent coining of the washer-like element 305.

Upon completion of the downward stroke of the punch 271, the punch is moved upwardly and the drive member 307 moves therewith. This allows the springs 295 to expand to return the components to the position shown in FIG. 10. However, in returning the inner die 285 to the initial position (FIG. 10) the inner die 285 forces the washer-like element 305 upwardly into the aperture 306 (FIG. 12) from which it is blanked out. As the inner die 285 is not retracted beneath the die cavity 287, the washer-like element 305 is not allowed to escape during the blanking operation. The washer-like element 305 is then carried with the sheet material 273 to a subsequent work station in which another tool (not shown in FIGS. 10-12) removes it from the sheet material 273.

A preferred construction for carrying out the concepts described with reference to FIGS. 10-12 is shown in FIGS. 13 and 14. Parts shown in FIGS. 13 and 14 which are identical to parts shown in FIGS. 10-12 are designated by corresponding reference numerals. As shown in FIGS. 13 and 14, a platen 311 is connected to a toolholder or punchholder 313 which mounts a plurality of the punches 271 and a plurality of knockout punches 315. the platen 311 may be of the type shown in FIGS. and 6 and may be driven by the press construction shown in FIGS. 5 and 6, if desired. The toolholder 313 is mounted on the platen 311 in any suitable manner such as by a plurality of screws 317. The punchholder 313 may be of any suitable construction.

The sheet material 275 may be advanced through the work stations by shuttle pads 318 and 318a in the same manner described hereinabove with reference to FIGS. 1-4. The sheet material 275 rests on the upper face of the die plate 281 and the upper faces of the several outer and inner dies as shown in FIGS. and 11. The die plate 281 also has a plurality of knockout dies 319 mounted therein for cooperating with the knockout punches 315 to remove the washer-like elements 305 (FIG. 12) from the apertures 306.

As shown in FIG. 13, the bolster 293 is slidably retained within a recess in the die plate 281 and the die plate 281 rests on the lower bolster 297, which in turn is mounted on a rigid, fixed support member 321.

A preferred form of driving the bolster 293 can best be understood from reference to FIG. 14. The platen 311 is supported by a pair of vertical platen posts 323 and 325 which are suitably rigidly affixed to the platen and which project downwardly therefrom through openings in the support member 321. The driving connection between the platen 311 and the bolster 293 is formed by a pair of drive members or bump rods 327 and a pair of headed members 328 affixed to the bolster 293. The bolster 293 is urged upwardly by the springs 295 which are retained within appropriate upwardly opening recesses in the lower bolster 297. The maximum upward position of the bolster 293 is defined by the engagement of the upper surfaces of the headed members 328 with surfaces 329 of the die plate 281. As the die plate 281 is suitably retained in a fixed position, the maximum upward position of the bolster 293 and hence of the inner dies 285 is correspondingly fixed. Preferably, in such maximum upward position the upper faces of the inner dies 285 are flush with the upper faces of the outer dies 283.

In the position shown in FIG. 14, the platen 311 is advanced downwardly to move the bolster 293 downwardly against the biasing force of the springs 295. With the bolster 293 in its uppermost position, the drive members 327 are retracted slightly within the die plate 281 and their end faces 331 are spaced from the upper surface of the members 328 to thereby allow some downward travel of the platen 331 with the punches 271 before the drive members 327 begin to urge the bolster 293 and hence the inner dies 285 downwardly. This initial spacing should be sufficient to allow the sections 277 of the punches 271 to perform the first work operation as described hereinabove with reference to FIG. 10.

Each of the drive members 327 has an upper end in the form of a screw 333 which is received in a correspondingly threaded bore 335. Accordingly, this permits vertical adjustment of the drive members 327 relative to the platen 311. This permits adjustment of the amount of travel of the platen 311 which can occur before the drive members 327 become operative to begin withdrawing the inner dies 285.

The assembly shown in FIGS. 13 and 14 also includes a primary pad 337 which performs the usual function of clamping the sheet material 275 against the upper surface of the die plate 285 during at least a portion of the advancing movement of the platen 311. The primary pad 337 is connected to the platen 311 by a plurality (two being illustrated in FIG. 14) of compound connector members 339. Each of the connector members 339 includes a bolt 341 affixed to the primary pad 337 at its lower end and having a head slidably received within a bore 343 formed in the platen 311 and the toolholder 313. The bolt 341 is urged downwardly by a spring 345 which is received in the bore 343. Each of the connector members 339 also includes a screw 347 connected to the bolt 341 and having an upper threaded portion 349. An adjusting nut 351 and a lock nut 353 are received on the screw 347. By turning of the adjusting nut 351 and the lock nut 353, the position of the connector member 339 relative to the platen 31 1 can be adjusted. This causes a corresponding movement on the part of the primary pad 337 to thereby permit adjustment of pad elevation in accordance with the lengths of the punches 271.

In the operation of the embodiment of FIGS. 1044, the drive members 327 are initially in an upward position in which the end faces 331 thereof are spaced upwardly from the headed members 328. The bolster 293 is retained in an upper position by the engagement of the upper faces of the headed members 328 with the surfaces 329 (FIG. 14). In this position, the upper faces of the dies 283 and 285 are substantially flush.

The platen 311 is then moved downwardly to perform a work operation such as the work operation shown in FIG. 10. At or near the completion of this work operation, the end faces 331 engage the upper faces of the headed members 328 whereupon further downward movement of the platen depresses the bolster 293 and the I dies 285 and causes the performance of a second work operation such as the blanking operation shown in FIG. 11. During the subsequent upward movement of the platen 311, the springs 295 return the bolster 293 to the upward position thereof and the blanked out part 305 is returned as shown in FIG. 12.

FIG. shows another mechanism for adjusting the position of the primary pad which mechanism may be incorporated into the construction of FIGS. 13 and 14 in lieu of the primary pad adjustment mechanism shown.

In FIG. 15 a primary pad 371 is connected to a platen 372 by a bolt 373 which passes through a bore 375 in the primary pad and through a bore in the platen-The end portions of the bolt 373 are threaded and nuts 377 and 379 are mounted thereon. A spring 381 urges the primary pad 371 downwardly away from the platen 372. Thus, by turning the nut 377 the vertical position of the primary pad 371 relative to the platen 372 can be adjusted. 1

Moreover, the bore 375 loosely receives the bolts 373 to thereby permit a small amount of relative horizontal movement between the primary pad 371 and the bolt 373. This permits the primary pad to move horizontally to accommodate the punches which extend therethrough as shown in FIG. 14.

Many'obvious changes can be made to the illustrated embodiments of the invention. For example, the press can be arranged to advance the sheet material through the work stations in either direction. The cams shown in FIGS. 5 and 6 can be either internal or external and each of the shuttle pads can be formed as two separate members in lieu ofa single apertured member as shown in FIGS. 1-4.

Although exemplary embodiments of the invention have been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of this invention.

lclaim:

l. A press for operating tooling means at a work station to perform work operations on sheet material com prising:

means for operating the tooling means to cause said tooling means to perform said work operation on the sheet material at said station;

releasable means for retaining the sheet material in position at least during the operation of said tooling means;

upper and lower shuttle pads on opposite sides of the sheet material adjacent the tooling means;

means defining a surface immediately beneath said lower shuttle pad;

means for moving said shuttle pads toward each other and into clamping relationship with the sheet material;

means for moving said shuttle pads relative to said surface from an initial position to a second position when the shuttle pads are in clamping relationship with the sheet material to thereby move the section of sheet material initially at said station to a predetermined location and to move a second section of sheet material to said station;

means for holding said shuttle pads out of substantial contact with said surface and out of substantial sliding contact with the remainder of the press at least during the movement of said shuttle pads from the initial position to the second position whereby frictional losses due to such movement is minimized;

means for moving said shuttle pads out of clamping relationship with the sheet material; and

means for returning the shuttle pads from said second position to said initial position.

2. A press as defined in claim 1 wherein each of said shuttle pads includes first and second portions located on opposite sides of the tooling means and offset from each other generally in the direction of the movement of the sheet material from the initial position to the second position.

3. A press as defined in claim 1 wherein said means for holding includes a carriage mounted for generally horizontal movement beneath said pads, said lower pad being mounted on and supported by said carriage.

4. A press for performing a work operation on sheet material and for advancing the sheet material through the press comprising:

a supporting structure;

a platen;

means for mounting the platen on the supporting structure for movement toward and away from the sheet material to allow a work operation to be performed on the sheet material;

upper and lower pads, the sheet material being adapted to be positioned between said pads; means for moving said pads generally toward and away from each other to clamp and unclamp the sheet material and in a shuttle motion to index the sheet material through the press; and said moving means including a power transmitting member, means for mounting said member on said supporting structure for pivotal movement relative thereto about a pivot axis, means for pivoting said member about said pivot axis to drive at least said one pad, and means for drivingly connecting said member and at least one of said pads for movement of at least said one pad, means for adjusting the location of said pivot axis while allowing said member to remain in the same position relative to the supporting structure whereby a characteristic of the motion of at least said one pad can be varied.

5. A press as defined in claim 4 wherein said member includes an arm and said pivot axis is intermediate the ends thereof, said means for pivoting includes a cam drivingly associated with said arm.

6. A press as defined in claim 5 wherein said moving means includes a carriage beneath said pads mounted for generally horizontal movement, means for drivingly connecting said carriage and said pads, a shaft affixed to said carriage and drivingly connected to said arm.

7. A press as defined in claim 6 wherein said lower pad is mounted on and supported by said carriage whereby said carriage holds said lower pad substantially out of sliding contact with other portions of the press, each of said pads including first and second portions for clamping regions of the sheet material on opposite sides of the location where the work operation is performed.

8. A press for performing a work operation on sheet material and for advancing the sheet material through the press comprising:

a supporting structure;

a platen;

means for mounting the platen on the supporting structure for movement toward and away from the sheet material to allow a work operation to be performed on the sheet material;

upper and lower secondary .pads, the sheet material being adapted to be positioned between said pads;

a carriage beneath said secondary pads;

means for mounting said carriage on said supporting structure for movement along a first path;

means for drivingly connecting said carriage and said secondary pads for movement of said secondary pads with said carriage along said first path;

means for mounting one of said secondary pads for movement relative to the other of said secondary pads along a second path to thereby permit said pads to clamp and unclamp the sheet material;

means for moving said pads relative to each other along said second path in a predetermined timed relationship with the movement of said carriage along said first path whereby the secondary pads can be utilized to index the sheet material through the press;

said supporting structure including a supporting member having a slot extending therethrough;

an arm having a slot extending therethrough, said arm being drivingly connected to said carriage;

a supporting shaft extending through both of said slots, said supporting member and said arm being relatively positionable about said shaft so that said slots are generally in registry;

first means for releasably mounting said shaft on said supporting member;

bearing means mounted on said shaft and at least partially in said slot of said arm for mounting said arm on said shaft for pivotal movement relative thereto about a pivotal axis whereby pivotal movement of said arm drives said carriage along said first path;

second means for releasably drivingly connecting at least a portion of said bearing means to said arm for pivotal movement therewith; and

means for retaining said arm on said bearing means whereby upon releasing of said first and second means said bearing means and said shaft can be moved in said slots relative to said arm and said supporting member to thereby move said pivot axis relative to both of said arm and said supporting member.

9. A press as defined in claim 8 wherein said drive means includes a drive member drivingly connected to one of said platen.

10. A press as defined in claim 8 wherein said drive means includes a drive member mounted on said platen for movement therewith and means for adjusting the position of said drive member relative to said platen to thereby adjust the point at which the drive member begins to move the inner die away from the sheet material.

11. A press as defined in claim 8 including a platelike member, means for mounting said inner die on said plate-like member, means for mounting said plate-like member for movement toward and away from the sheet material, said resilient means including at least one spring for urging the plate-like member toward the sheet material, and said drive means includes a drive member driven by said platen into driving engagement with said plate-like member.

12. A press as defined in claim 3 wherein said surface is intermediate said carriage and said lower shuttle pad.

13. A press for performing a work operation on sheet material and for advancing the sheet material through the press comprising:

a supporting structure;

a platen;

means for mounting the platen on the supporting structure for movement toward and away from the sheet material to allow a work operation to be performed on the sheet material;

upper and lower shuttle members, the sheet material being adapted to be positioned between said shut- Y He members;

a carriage beneath said shuttle members;

means for mounting said carriage on said supporting structure for movement along a first path;

means for moving said carriage along said first path,

, said last mentioned means including a first rotatable cam, an arm pivotally mounted on the supporting structure and engageable with and pivotable by said first cam, and means for drivingly connecting the arm and the carriage;

means for drivingly connecting said carriage and at least one of said shuttle members for movement of said one shuttle member with said carriage along said first path;

means for mounting the other of said shuttle members for movement with said carriage along the first path and relative to the carriage along a second path to thereby permit said shuttle members to clamp and unclamp the sheet material, said last mentioned mounting means including a passage extending through said carriage and a mounting member connected to said other pad and projecting through said passage;

a second arm pivoted to said supporting structure for driving said mounting member axially in said passage;

a second cam engageable with the second arm for pivoting said second arm; and

means including relatively sliding surfaces for drivingly connecting said second arm and said mounting member to allow said second arm to drive said mounting member axially in said passage and to allow said mounting member to move with said carriage along said first path relative to said second arm whereby said shuttle members can be utilized to index the sheet material through the press.

14. A press as defined in claim 13 including a third cam for driving the platen, a shaft mounted for rotation on said supporting structure, said first, second and third cams being mounted on said shaft for rotation therewith.

15. A press as defined in claim 13 wherein said means for mounting said carriage includes at least one rod mounted for reciprocating movement on said supporting structure and affixed to said carriage, said first arm being drivingly connected to said rod.

16. A press as defined in claim 13 wherein said first cam includes first and second cam surfaces for pivoting said first arm in first and second directions, respectively, about the pivotal axis of said first arm. 

1. A press for operating tooling means at a work station to perform work operations on sheet material comprising: means for operating the tooling means to cause said tooling means to perform said work operation on the sheet material at said station; releasable means for retaining the sheet material in position at least during the operation of said tooling means; upper and lower shuttle pads on opposite sides of the sheet material adjacent the tooling means; means defining a surface immediately beneath said lower shuttle pad; means for moving said shuttle pads toward each other and into clamping relationship with the sheet material; means for moving said shuttle pads relative to said surface from an initial position to a second position when the shuttle pads are in clamping relationship with the sheet material to thereby move the section of sheet material initially at said station to a predetermined location and to move a second section of sheet material to said station; means for holding said shuttle pads out of substantial contact with said surface and out of substantial sliding contact with the remainder of the press at least during the movement of said shuttle pads from the initial position to the second position whereby frictional losses due to such movement is minimized; means for moving said shuttle pads out of clamping relationship with the sheet material; and means for returning the shuttle pads from said second position to said initial position.
 2. A press as defined in claim 1 wherein each of said shuttle pads includes first and second portions located on opposite sides of the tooling means and offset from each other generally in the direction of the movement of the sheet material from the initial position to the second position.
 3. A press as defined in claim 1 wherein said means for holding includes a carriage mounted for generally horizontal movement beneath said pads, said lower pad being mounted on and supported by said carriage.
 4. A press for performing a work operation on sheet material and for advancing the sheet material through the press comprising: a supporting structure; a platen; means for mounting the platen on the supporting structure for movement toward and away from the sheet material to allow a work operation to be performed on the sheet material; upper and lower pads, the sheet material being adapted to be positioned between said pads; means for moving said pads generally toward and away from each other to clamp and unclamp the sheet material and in a shuttle motion to index the sheet material through the press; and said moving means including a power transmitting member, means for mounting said member on said supporting structure for pivotal movement relative thereto about a pivot axis, means for pivoting said member about said pivot axis to drive at least said one pad, and means for drivingly connecting said member and at least one of said pads for movement of at least said one pad, means for adjusting the location of said pivot axis while allowing said member to remain in the same position relative to the supporting structure whereby a characteristic of the motion of at least said one pad can be varied.
 5. A press as defined in claim 4 wherein said member includes an arm and said pivot axis is intermediate the ends thereof, said means for pivoting includes a cam drivingly associated with said arm.
 6. A press as defined in claim 5 wherein said moving means includes a carriage beneath said pads mounted for generally horizontal movement, means for drivingly connecting said carriage and said pads, a shaft affixed to said carriage and drivingly connected to said arm.
 7. A press as defined in claim 6 wherein said lower pad is mounted on and supported by said carriage whereby said carriage holds said lower pad substantially out of sliding contact with other portions of the press, each of said pads including first and second portions for clamping regions of the sheet material on opposite sides of the location where the work operation is performed.
 8. A press for performing a work operation on sheet material and for advancing the sheet material through the press comprising: a supporting structure; a platen; means for mounting the platen on the supporting structure for movement toward and away from the sheet material to allow a work operation to be performed on the sheet material; upper and lower secondary pads, the sheet material being adapted to be positioned between said pads; a carriage beneath said secondary pads; means for mounting said carriage on said supporting structure for movement along a first path; means for drivingly connecting said carriage and said secondary pads for movement of said secondary pads with said carriage along said first path; means for mounting one of said secondary pads for movement relative to the other of said secondary pads along a second path to thereby permit said pads to clamp and unclamp the sheet material; means for moving said pads relative to each other along said second path in a predetermined timed relationship with the movement of said carriage along said first path whereby the secondary pads can be utilized to index the sheet material through the press; said supporting structure including a supporting member having a slot extending therethrough; an arm having a slot extending therethrough, said arm being drivingly connected to said carriage; a supporting shaft extending through both of said slots, said supporting member and said arm being relatively positionable about said shaft so that said slots are generally in registry; first means for releasably mounting said shaft on said supporting member; bearing means mounted on said shaft and at least partially in said slot of said arm for mounting said arm on said shaft for pivotal movement relative thereto about a pivotal axis whereby pivotal movement of said arm drives said carriage along said first path; second means for releasably drivingly connecting at least a portion of said bearing means to said arm for pivotal movement therewith; and means for retaining said arm on said bearing means whereby upon releasing of said first and second means said bearing means and said shaft can be moved in said slots relativE to said arm and said supporting member to thereby move said pivot axis relative to both of said arm and said supporting member.
 9. A press as defined in claim 8 wherein said drive means includes a drive member drivingly connected to one of said platen.
 10. A press as defined in claim 8 wherein said drive means includes a drive member mounted on said platen for movement therewith and means for adjusting the position of said drive member relative to said platen to thereby adjust the point at which the drive member begins to move the inner die away from the sheet material.
 11. A press as defined in claim 8 including a plate-like member, means for mounting said inner die on said plate-like member, means for mounting said plate-like member for movement toward and away from the sheet material, said resilient means including at least one spring for urging the plate-like member toward the sheet material, and said drive means includes a drive member driven by said platen into driving engagement with said plate-like member.
 12. A press as defined in claim 3 wherein said surface is intermediate said carriage and said lower shuttle pad.
 13. A press for performing a work operation on sheet material and for advancing the sheet material through the press comprising: a supporting structure; a platen; means for mounting the platen on the supporting structure for movement toward and away from the sheet material to allow a work operation to be performed on the sheet material; upper and lower shuttle members, the sheet material being adapted to be positioned between said shuttle members; a carriage beneath said shuttle members; means for mounting said carriage on said supporting structure for movement along a first path; means for moving said carriage along said first path, said last mentioned means including a first rotatable cam, an arm pivotally mounted on the supporting structure and engageable with and pivotable by said first cam, and means for drivingly connecting the arm and the carriage; means for drivingly connecting said carriage and at least one of said shuttle members for movement of said one shuttle member with said carriage along said first path; means for mounting the other of said shuttle members for movement with said carriage along the first path and relative to the carriage along a second path to thereby permit said shuttle members to clamp and unclamp the sheet material, said last mentioned mounting means including a passage extending through said carriage and a mounting member connected to said other pad and projecting through said passage; a second arm pivoted to said supporting structure for driving said mounting member axially in said passage; a second cam engageable with the second arm for pivoting said second arm; and means including relatively sliding surfaces for drivingly connecting said second arm and said mounting member to allow said second arm to drive said mounting member axially in said passage and to allow said mounting member to move with said carriage along said first path relative to said second arm whereby said shuttle members can be utilized to index the sheet material through the press.
 14. A press as defined in claim 13 including a third cam for driving the platen, a shaft mounted for rotation on said supporting structure, said first, second and third cams being mounted on said shaft for rotation therewith.
 15. A press as defined in claim 13 wherein said means for mounting said carriage includes at least one rod mounted for reciprocating movement on said supporting structure and affixed to said carriage, said first arm being drivingly connected to said rod.
 16. A press as defined in claim 13 wherein said first cam includes first and second cam surfaces for pivoting said first arm in first and second directions, respectively, about the pivotal axis of said first arm. 